Copper ions inhibit the demineralisation of human enamel

Cu2+ is cariostatic in rats reportedly due to it bacteriocidal, properties. Here, we report the use of a simple abiotic model system to investigate whether Cu2+ has any inhibitory effect on the acid dissolution of human enamel. Crowns were exposed to a sequence of seven 10 mmol/l acetic acid challenges. The mineral dissolved during each challenge was then determined. CuSo(4) (10 mmol/l) was present during the fourth of these challenges. Loss of calcium and phosphate were reduced by 57 and 63%, respectively, (P < 0.0001) in the presence Of Cu2+. Losses were also significantly reduced during the next acidic challenge in the absence Of Cu2+ The degree of protection was found to approach maximum at about 5 mmol/l Cu2+ The well-known cariostatic properties Of Cu2+ may therefore be due not only to its ability to inhibit bacterial. growth but also to its ability to directly inhibit acid dissolution of enamel. (C) 2002 Elsevier Science Ltd. All rights reserved.